Abstract : The mid-pulse detector may be used in a receiver to detect the exact time of arrival of a pulse. The mid-pulse detector operation is based upon the principle that the instantaneous phase reversal of a carrier frequency can be readily detected as a zero-crossing of the amplitude modulation function, or waveform. In the prior art, leading edge detection has been used to determine pulse arrival time. The mid-pulse detector of this invention detects a zero-crossing of the modulation function and eliminates this sensitivity to signal amplitude. Another prior art method of mid-pulse detection is the pulse-differentiation technique. This method is sensitive to pulse envelope distortions, which cause the pulse peak to shift relative to the true mid-pulse. Here, again, the phase-locking mid-pulse detector has the advantages of being insensitive to pulse-envelope modulation.